When opened on April 29, three tightly clustered bids exceeded the engineer’s estimate by almost $300 million for boring a mile-long tunnel under the Thimble Shoal Channel near Norfolk, Virginia. The mistake puts the owner, the Chesapeake Bay Bridge-Tunnel (CBBT) District, in the difficult position of having to substantially reduce costs on an aggressively bid design-build project in order to meet its constrained budget.